Last week, I went to an event aimed at female healthcare scientists. My feelings about it are mixed and I could probably write another entire post about it. As a very brief summary, although I found some parts of it interesting and useful, I was frustrated at references to well-worn stereotypes - women are 'nurturing' and good at multi-tasking - and the generally quite binary nature of some of the discussion.
Leading on from that, today I was told that feminism - at least where "self-proclaimed feminists" are concerned - "is not about equality".
I'm disappointed that I didn't feel able to speak up properly in this particular situation. There were a number of contributory factors. For example, one of the people involved enjoys winding people up. I do not enjoy being wound up, and it's not a good position from which to start a conversation about something which means a lot to me.
Also, I was at work, and by 'at work' I mean 'actively engaged in doing something'. It wasn't an appropriate time to have an in-depth conversation - I wouldn't have been able to concentrate on both what I was doing and a complex conversation, and I wouldn't expect other people to either.
But it doesn't sit well with me not to say anything. How can things change if nobody speaks up? What is the point of me feeling strongly about something, if I keep it all in my own head, or talk about it only to a group of like-minded and supportive friends?
On top of all that, I am acutely aware that my interpretation of the world around me is the most unique and important thing I can ever contribute to anything, be it professional or personal. So if I feel silenced and ignored and I'm hurt by that, then it's not enough to curl up under the duvet and feel sorry for myself, much though I might want to. I have to speak up somewhere and somehow, or I'm complicit in my own voicelessness.
I believe that feminism is about equality. Feminism is working towards equality for everyone, regardless of race, background, belief or gender.
Feminism is the reason I can vote and own property and work. Feminism has allowed me to choose whether or not to have children, or marry, and what career to pursue.
Feminism is me using my privilege as a well-educated, white, cis-gendered woman to lift up people who don't have those advantages. Feminism is the way I try to make the world a better place. Feminism is having the difficult conversations, when and where I can, so that other people might not have to. Feminism is making the world a safe place for everyone.
Feminism is knowing that when the world says I'm not feminine enough, I'm not clever enough, I'm just not enough - that this is so much drivel. Feminism is me not having to feel awkward or ashamed for rarely wearing make-up, and each of us having the choice to wear it if we want to.
Feminism is not being limited by the expectations other people place on us. Feminism is no-one else having to hear derogatory comments about female physicists or male nurses.
Feminism is recognising that everyone should be able to express their emotions without judgement, and working towards a world where men can talk about their feelings instead of dying from them.
Feminists are not a homogeneous group, so it would be naive to expect that I will agree with all feminists on all issues. But also, humanity is diverse, and diversity is our superpower.
I am a feminist because I want the world to be a better place. I want people to be kinder to each other and to lift each other up, and I know that this can't happen without change, and change doesn't happen by accident, without work. Feminism is doing this work, in all the little or large ways that I can, to make the better place a reality.
Tuesday 8 May 2018
Friday 12 February 2016
A Snapshot of Radiotherapy Physics: 4DCT
The centre I work at is in the process of commissioning 4DCT for some radiotherapy planning, so this seemed like a good moment to try to explain what 4DCT is, and why we use it.
Let's start with the basics - 'standard' CT [computed tomography]. Sometimes called a 'CAT' scan [computed axial tomography], CT is used extensively in diagnostic radiology. It's the doughnut-shaped one in which an x-ray source and detector array spin around (usually around one rotation per second) while the couch on which the patient lies moves through the bore of the scanner. (Not to be confused with the doughnut-shaped one which is very loud, uses a magnet, and which many people find terribly claustrophobic - that's MRI [magnetic resonance imaging]).
The signal received by the detectors varies depending on what's between the x-ray source and the detectors - more or denser tissue between the two means less of the x-ray beam gets through the patient to the detector. The signal from each projection - every angle at which x-rays pass through the patient - is analysed and used to reconstruct regions of different density within the patient, forming axial (slice) images from head to toe - or whichever bits are required!
In radiotherapy, we use CT scans to plan treatment. The way radiation dose is deposited in tissue is determined largely by electron density (at least for megavoltage photon beams, which are used for the majority of radiotherapy), which is related to the density and composition of the tissue. That means that if we know the relationship between electron density and CT number (how bright or dark a pixel is on the CT image) for a CT scanner, we can use the information from the CT scan to accurately model the therapeutic radiation dose we give each patient.
So, that's a standard CT scan, and that's all that's required for the majority of patients. Some parts of the human body are constantly moving1 - particularly in the thorax, where all sorts of mobile things are located, including the oesophagus, diaphragm and lungs - and this can pose a problem when planning treatment of tumours in these areas. As I mentioned, CT tube rotation for standard protocols is usually around one second per rotation, and a ballpark figure for couch speed (speed of motion through the x-ray beam) is perhaps 1 mm/s - that will only give a snapshot of a lung tumour for a normal breathing rate of around 15-20 breaths per minute. All the detailed information the CT scan provides is specific to that point in the patient's breathing cycle, and breathing patterns - speed and range of motion - vary from person to person.
So how do we know where the tumour will be, if it's moving and we only have a snapshot of its position? Well, with a standard CT scan, we don't. One way of getting around this is to add a margin to the treatment volume to allow for the uncertainty in position - but that has to be done using information about the 'average' breathing pattern, and not all patients are average.
Enter 4DCT! The fourth dimension, of course, is time, added to the three dimensional CT scan we normally acquire. The couch speed is slowed down so that we can acquire additional information for each image slice - each position within the patient - information which covers more of the breathing cycle. Information about the patient's breathing during the scan is also acquired (by various methods, e.g. reflective markers on the patient's abdomen or using an elasticated belt), and used by the CT scanner to separate the images acquired according to the part of the breathing cycle.
Usually the breathing cycle is split into ten phases, giving us ten complete sets of CT images which cover the whole range of tumour motion. So instead of adding an 'average' margin to account for tumour motion, we can actually look at how the tumour moves, and plan treatment to cover the tumour over the whole breathing cycle.
(An appalling absence of three years in updating this blog! One of my new year's resolutions for 2016 was to write more; specifically, to finish the Medical Physics series - if I could ever consider it finished, with the variety of things we do!)
Let's start with the basics - 'standard' CT [computed tomography]. Sometimes called a 'CAT' scan [computed axial tomography], CT is used extensively in diagnostic radiology. It's the doughnut-shaped one in which an x-ray source and detector array spin around (usually around one rotation per second) while the couch on which the patient lies moves through the bore of the scanner. (Not to be confused with the doughnut-shaped one which is very loud, uses a magnet, and which many people find terribly claustrophobic - that's MRI [magnetic resonance imaging]).
The signal received by the detectors varies depending on what's between the x-ray source and the detectors - more or denser tissue between the two means less of the x-ray beam gets through the patient to the detector. The signal from each projection - every angle at which x-rays pass through the patient - is analysed and used to reconstruct regions of different density within the patient, forming axial (slice) images from head to toe - or whichever bits are required!
In radiotherapy, we use CT scans to plan treatment. The way radiation dose is deposited in tissue is determined largely by electron density (at least for megavoltage photon beams, which are used for the majority of radiotherapy), which is related to the density and composition of the tissue. That means that if we know the relationship between electron density and CT number (how bright or dark a pixel is on the CT image) for a CT scanner, we can use the information from the CT scan to accurately model the therapeutic radiation dose we give each patient.
So, that's a standard CT scan, and that's all that's required for the majority of patients. Some parts of the human body are constantly moving1 - particularly in the thorax, where all sorts of mobile things are located, including the oesophagus, diaphragm and lungs - and this can pose a problem when planning treatment of tumours in these areas. As I mentioned, CT tube rotation for standard protocols is usually around one second per rotation, and a ballpark figure for couch speed (speed of motion through the x-ray beam) is perhaps 1 mm/s - that will only give a snapshot of a lung tumour for a normal breathing rate of around 15-20 breaths per minute. All the detailed information the CT scan provides is specific to that point in the patient's breathing cycle, and breathing patterns - speed and range of motion - vary from person to person.
So how do we know where the tumour will be, if it's moving and we only have a snapshot of its position? Well, with a standard CT scan, we don't. One way of getting around this is to add a margin to the treatment volume to allow for the uncertainty in position - but that has to be done using information about the 'average' breathing pattern, and not all patients are average.
Enter 4DCT! The fourth dimension, of course, is time, added to the three dimensional CT scan we normally acquire. The couch speed is slowed down so that we can acquire additional information for each image slice - each position within the patient - information which covers more of the breathing cycle. Information about the patient's breathing during the scan is also acquired (by various methods, e.g. reflective markers on the patient's abdomen or using an elasticated belt), and used by the CT scanner to separate the images acquired according to the part of the breathing cycle.
Usually the breathing cycle is split into ten phases, giving us ten complete sets of CT images which cover the whole range of tumour motion. So instead of adding an 'average' margin to account for tumour motion, we can actually look at how the tumour moves, and plan treatment to cover the tumour over the whole breathing cycle.
1. OK, on some level, everything in the human body is constantly moving; in practical terms, though, it's a matter of how large, how much and how fast.
(An appalling absence of three years in updating this blog! One of my new year's resolutions for 2016 was to write more; specifically, to finish the Medical Physics series - if I could ever consider it finished, with the variety of things we do!)
Thursday 19 September 2013
Sonnet 66: recast for one suffering a malady of motion
[The protaganist boards an omnibus. Finding there to be only single seats available, save for the back row, she is moved to wonder where she should sit.]
The back, or not the back - that is the question:
Whether 'tis easier on the stomach to suffer
The bumps and jolts of ev'ry tortu'us turning
Or to bump arms against another traveler
And pile bags on sickly lap. The back, the space--
The space, and yet not space, if entr'ing on
Another, nay, a thousand other men
To sit beside us. 'Tis a complication
Devoutly to be fled. The back, the space -
The space - and yet, the lurch. Ay, there's the rub,
For in that pitch and heave, what qualms may come
When we have settled on this jarring stall,
Must give us pause. There's the respect
That makes calamity of such long trips...
Thursday 20 June 2013
Benevolent sexism & missing the point
I recently came across a thought-provoking article entitled 'Compliments, sexism and careers in science' by Suzie Sheehy, a physicist working at the STFC Rutherford Appleton Laboratory. The article discusses the existence of 'benevolent sexism', quoting the following definition from a paper by Peter Glick and Susan Fiske1:
Consider the following comment by Barbara Montanari, which I think highlights a key issue with the original remark:
It can be argued, quite reasonably, that the associations I've made were not what the speaker intended, and that other people may see different interpretations. However, in the context of today's society, where sexist generalisations sadly still exist, I think it's important to at least be aware of such connotations, as they risk feeding into and perpetuating societal ideas of what it means to be male or female. (In a similar way, the inflexible marketing of dolls and toy kitchen sets for girls, versus construction sets or – disappointingly – science sets for boys may influence children's ideas of appropriate gendered behaviour.)
Moving on, another comment by Stefano C. serves to highlight some of the wider problems in gender relations:
Easier to address is the fact that the commenter seems to be conflating the ideas of equality and identity. No-one is suggesting that men and women are identical. But, as I see it, the ideal towards which feminism strives is for there to be equality of opportunity for, and conduct towards, both men and women. Something which, sadly, still doesn’t yet exist.
Stefano also says:
...but he does act differently towards a person based on their gender, and therefore, this is sexism. I am a woman. I am also an adult, and I don't want or need men to act any more nicely or kindly towards me than they would to any other human being. I am quite capable of dealing with social interaction without anyone's deliberate self-censorship (which, by the way, smacks of an out-dated desire to protect women's delicate sensibilities).
Stefano continues to miss the point when he addresses Suzie’s encounter with a stranger at a conference:
As I said, a thought-provoking article, and a subject which doesn't lend itself to glib or concise answers. Then again, that's part of what makes it so worthwhile thinking about.
Benevolent sexism is defined as a set of interrelated attitudes toward women that are sexist in terms of viewing women stereotypically and in restricted roles but that are subjectively positive in feeling tone (for the perceiver) and also tend to elicit behaviours typically categorized as prosocial (e.g., helping) or intimacy-seeking (e.g., self-disclosure)One of the things I find particularly interesting is how many of the commenters assume that the issue with the phrase 'lovely ladies' is a reference to the women's appearance. But Suzie herself never makes this link, and, in my opinion, those comments are rather missing the point of the article. The phrase 'lovely ladies' is not necessarily any less problematic when you consider the word 'lovely' to refer, primarily, to the pleasant demeanour of the women giving a talk.
Consider the following comment by Barbara Montanari, which I think highlights a key issue with the original remark:
The problem is not that the teacher called you “lovely ladies”. The problem is that people’s preconception of a scientist is very narrow. Surely you can’t be lovely ladies and be good scientists at the same time! You do not fit the mould. We need to smash the mould. Anybody can be a scientist, no matter what their physical or character traits are.The inference I draw from this is that it is desirable for ladies to be lovely. While in many ways, the world would be a better place if we were all lovely, it makes me uncomfortable to suggest breaking one stereotype – that of the (female) scientist – by potentially reinforcing another: that of the 'proper' woman, a woman defined by a set of qualities (loveliness, caring, empathy) which are not fundamentally gendered, but which society has assigned to a gendered norm.
It can be argued, quite reasonably, that the associations I've made were not what the speaker intended, and that other people may see different interpretations. However, in the context of today's society, where sexist generalisations sadly still exist, I think it's important to at least be aware of such connotations, as they risk feeding into and perpetuating societal ideas of what it means to be male or female. (In a similar way, the inflexible marketing of dolls and toy kitchen sets for girls, versus construction sets or – disappointingly – science sets for boys may influence children's ideas of appropriate gendered behaviour.)
Moving on, another comment by Stefano C. serves to highlight some of the wider problems in gender relations:
When it comes to this topic I always feel that the ultimate goal that I hear people talking about, that is gender equality, is wrong. Men and woman are not equal at all, they have different sensibilities, different point of views, somehow even different brains, capable to deal with the same things in a different way. This is one of the things that makes the world so richer. But being different doesn’t mean being superior or inferior. Electrons and neutrinos are very different but also part of the same doublet, aren’t they :) ?It's far beyond the scope of this blog post to address the perceived physical and mental differences between men and women versus any which have been scientifically proven – I am, after all, writing a blog and not a PhD thesis. (It's also not particularly helpful to take apart the commenter's poor choice of analogy, so I'll just note that neutrinos have fuck all impact on the majority of normal matter.)
Easier to address is the fact that the commenter seems to be conflating the ideas of equality and identity. No-one is suggesting that men and women are identical. But, as I see it, the ideal towards which feminism strives is for there to be equality of opportunity for, and conduct towards, both men and women. Something which, sadly, still doesn’t yet exist.
Stefano also says:
I personally don’t feel guilty if I’m just nice and kind with a woman in a different way that I’m with a man but I never think that any gender is superior to the other.This is, I think, a perfect example of benevolent sexism: he is being 'nice and kind', unarguably positive ways to behave towards any person. He consciously doesn't think that any gender is superior!
...but he does act differently towards a person based on their gender, and therefore, this is sexism. I am a woman. I am also an adult, and I don't want or need men to act any more nicely or kindly towards me than they would to any other human being. I am quite capable of dealing with social interaction without anyone's deliberate self-censorship (which, by the way, smacks of an out-dated desire to protect women's delicate sensibilities).
Stefano continues to miss the point when he addresses Suzie’s encounter with a stranger at a conference:
Concerning the second example, I think it has nothing to do with benevolent or hostile sexism. It was simply a guy that wanted to impress you. Even if it was in a conference I don’t think its comment was in anyway related to your being a scientist.No, the comment wasn't related to her being a scientist – this, given the context of a scientific conference, and a delegate who was a complete stranger, is what makes it entirely inappropriate. As for trying to impress her – would he have done this if she had been a man? Almost certainly not.
As I said, a thought-provoking article, and a subject which doesn't lend itself to glib or concise answers. Then again, that's part of what makes it so worthwhile thinking about.
1. Glick, P & Fiske, S T. 1996. The Ambivalent Sexism Inventory: Differentiating hostile and benevolent sexism. J. Pers. Soc. Psychol. 70(3):491-512. dx.doi.org/10.1037//0022-3514.70.3.491
Monday 22 April 2013
Nuclear Medicine (Medical Physics series, part 2)
Nuclear medicine, in a nutshell, involves injecting - or otherwise dosing - people with radioactive substances. The rest of diagnostic radiology deals with images created using an external radiation source; nuclear medicine is very much internal. One exciting result of this is that while x-rays, MRI and the like show anatomy brilliantly, nuclear medicine is able to show the functional state of an organ or tissue.
For example, this image shows the pelvis and legs of a patient with arthritis. You can see the worst affected areas (the left knee and ankle); the increased cell activity engaged in repairing the damage caused by arthritis means that the cells take up more of the radioactive tracer, and show up more brightly on the scan. In addition, you can see the patient's bladder - the standard route of excretion for many substances, radioactive or otherwise!
As with all areas of medical physics, nuclear medicine involves a lot of quality assurance: physicists test equipment weekly, and monthly, and six monthly; they carry out detailed surveys of equipment prior to first clinical use, and after maintenance, and any time something seems to not quite be working correctly. Most equipment tests in nuclear medicine are associated with image quality - checking that a camera's spatial and contrast resolution aren't degrading to a point where clinical use is compromised, for example. Some non-imaging equipment is used as well, though, for example well calibrators (used to measure the activity of radiation in a patient injection) or gamma counters (used to quantify the radiation emitted by blood samples), and these need testing too.
On the clinical side of things, nuclear medicine physicists look at quantitative (or semi-quantitative) analysis of data. Sometimes that data involves images; assessment of the change in activity (recorded counts, pixel value) within an area over time, for example, or the total activity taken up in an area. I did a project during my placement in nuclear medicine looking at the (then current) protocol for calculating thyroid uptake index (a measure of thyroid function) vs. two different methods using commercial software, aiming to assess the differences and the potential impact of changing the protocol. Sometimes there are no images at all - several pages of my training portfolio concentrated solely on calculating glomerular filtration rate - a measure of kidney function - and I could bore you about it for days.
In addition to the above, the radiopharmacy - responsible for producing individual patient doses of the required pharmaceutical (different tracers for different purposes) - will have physicists involved somewhere. Depending on the department, it may be a physics-led radiopharmacy, or it may be led by pharmacists and supported by physicists; in either case, physicists will advise on radiation protection issues and ensure that the department complies with the relevant legislation.
The final area of nuclear medicine is radionuclide therapy (RNT): actually treating conditions using radiopharmaceuticals. One of the most common conditions treated in this way is an over-active thyroid. The thyroid takes up iodine, so by giving patients a radioactive form of iodine, it's possible to kill cells in the thyroid - reducing function to a normal level - without killing cells elsewhere in the body1. Physicists are required by law to be involved in RNT, and may administer the radio-isotope or provide advice and information to patients about to undergo RNT.
RNT can also be used to treat disorders where cells are growing out of control, such as polycythemia vera, a disorder in which too many blood cells are produced, and even metastases from cancer2. As well as benign thyroid conditions, radioiodine is also used to treat thyroid cancer, for which patients are treated with a high activity of radioiodine and so have to spend three or four days as an in-patient in a lead-shielded room. This minimises the exposure of the general public (including family and friends) to radiation, and physicists are instrumental in calculating just how long the patient should stay in hospital, and how long visitors may be present for on each day.
Nuclear medicine physicists also need to consider the scope and impact of a lot of legislation, perhaps more - at least in number of applicable statutory instruments! - than in any other area of medical physics. Legislation, however, is complex enough to require its own post.
Next time: diagnostic radiology, the purpose of which you might well be able to glean from the name...!
For example, this image shows the pelvis and legs of a patient with arthritis. You can see the worst affected areas (the left knee and ankle); the increased cell activity engaged in repairing the damage caused by arthritis means that the cells take up more of the radioactive tracer, and show up more brightly on the scan. In addition, you can see the patient's bladder - the standard route of excretion for many substances, radioactive or otherwise!As with all areas of medical physics, nuclear medicine involves a lot of quality assurance: physicists test equipment weekly, and monthly, and six monthly; they carry out detailed surveys of equipment prior to first clinical use, and after maintenance, and any time something seems to not quite be working correctly. Most equipment tests in nuclear medicine are associated with image quality - checking that a camera's spatial and contrast resolution aren't degrading to a point where clinical use is compromised, for example. Some non-imaging equipment is used as well, though, for example well calibrators (used to measure the activity of radiation in a patient injection) or gamma counters (used to quantify the radiation emitted by blood samples), and these need testing too.
On the clinical side of things, nuclear medicine physicists look at quantitative (or semi-quantitative) analysis of data. Sometimes that data involves images; assessment of the change in activity (recorded counts, pixel value) within an area over time, for example, or the total activity taken up in an area. I did a project during my placement in nuclear medicine looking at the (then current) protocol for calculating thyroid uptake index (a measure of thyroid function) vs. two different methods using commercial software, aiming to assess the differences and the potential impact of changing the protocol. Sometimes there are no images at all - several pages of my training portfolio concentrated solely on calculating glomerular filtration rate - a measure of kidney function - and I could bore you about it for days.
In addition to the above, the radiopharmacy - responsible for producing individual patient doses of the required pharmaceutical (different tracers for different purposes) - will have physicists involved somewhere. Depending on the department, it may be a physics-led radiopharmacy, or it may be led by pharmacists and supported by physicists; in either case, physicists will advise on radiation protection issues and ensure that the department complies with the relevant legislation.
The final area of nuclear medicine is radionuclide therapy (RNT): actually treating conditions using radiopharmaceuticals. One of the most common conditions treated in this way is an over-active thyroid. The thyroid takes up iodine, so by giving patients a radioactive form of iodine, it's possible to kill cells in the thyroid - reducing function to a normal level - without killing cells elsewhere in the body1. Physicists are required by law to be involved in RNT, and may administer the radio-isotope or provide advice and information to patients about to undergo RNT.
RNT can also be used to treat disorders where cells are growing out of control, such as polycythemia vera, a disorder in which too many blood cells are produced, and even metastases from cancer2. As well as benign thyroid conditions, radioiodine is also used to treat thyroid cancer, for which patients are treated with a high activity of radioiodine and so have to spend three or four days as an in-patient in a lead-shielded room. This minimises the exposure of the general public (including family and friends) to radiation, and physicists are instrumental in calculating just how long the patient should stay in hospital, and how long visitors may be present for on each day.
Nuclear medicine physicists also need to consider the scope and impact of a lot of legislation, perhaps more - at least in number of applicable statutory instruments! - than in any other area of medical physics. Legislation, however, is complex enough to require its own post.
Next time: diagnostic radiology, the purpose of which you might well be able to glean from the name...!
1. Technically, this isn't quite true: of course some cells in the rest of the body will be affected. But it's a numbers game, and the huge affinity of the thyroid for iodine means that very little of it reaches the rest of the body.
2. For a particularly exciting use of RNT in metastatic cancer, look up Alpharadin: its use in prostate cancer patients was so effective that the trial was actually ended early.
Thursday 14 March 2013
Medical Physics: An Introduction (Medical Physics series, part 1)
In December 2009, a dear friend of mine asked me a very big question. 'Tell us all about medical physics,' she said. 'What's it about?'
At this point, I had only known of the existence of medical physics for about six months. Approximately 30 seconds after finding out about it, I wanted to do it, and by December I had arranged two work experience visits and a tour of a third department, but I still had no idea how to describe it.
I've now been in the job around two and a half years, and it's still hard to describe. It's so big! It really is. My standard answer has become 'anything involving radiation in hospitals', and that's a fair simplification, but doesn't really explain to anyone what I do all day. It also tends to lead to a stock series of responses, including 'oh, you're a radiographer?' (no) 'oh, you're a radiologist?' (no) and 'oh, you fix [insert medical machine here]??' (no). In order: radiographers push buttons which make images (or treat patients, in radiotherapy); radiologists are doctors specialising in radiology (medical imaging), and engineers fix machines. (We just tell the engineer it's broken...)
Wikipedia1 helpfully describes medical physics as follows:
Well, as I said above, mainly radiation; to be specific, ionising radiation. That is, x-rays, radioactive materials, etc. Since that's the bulk of it, and that's what I'm working in, I'll come to the details of that later.
But as well as ionising radiation, we also work with non-ionising radiation: lasers (used to break up kidney stones, remove tattoos, etc.), ultrasound (obviously used in imaging, but also in interventional medicine), UV dermatological treatments (for psoriasis and certain skin cancers), and magnetic resonance imaging (MRI).
The main roles in a lot of this are quality assurance, and safety. We test machines; we look for patterns in response, for abnormalities, and we try to explain them. (Then we call the engineers...) We advise doctors, and other medical staff, on the safety issues with various types of non-ionising radiation (don't shine lasers into your eyes; don't take metallic power tools into an MRI room2; in terms of ultrasound, well, there's very little safety to advise on, which is one of the reasons I personally find it dull).
We also try to optimise imaging: obtaining the best quality image possible (for a definition of quality which depends on the clinical purpose), and writing computer programs to help with image processing and analysis. This is also to do with safety, in terms of reducing the dose of radiation needed to achieve an appropriate image quality.
In ionising radiation, there are three main areas: nuclear medicine, radiotherapy, diagnostic radiology; and covering all of these, radiation protection. I'll explain these in more detail in following posts.
At this point, I had only known of the existence of medical physics for about six months. Approximately 30 seconds after finding out about it, I wanted to do it, and by December I had arranged two work experience visits and a tour of a third department, but I still had no idea how to describe it.
I've now been in the job around two and a half years, and it's still hard to describe. It's so big! It really is. My standard answer has become 'anything involving radiation in hospitals', and that's a fair simplification, but doesn't really explain to anyone what I do all day. It also tends to lead to a stock series of responses, including 'oh, you're a radiographer?' (no) 'oh, you're a radiologist?' (no) and 'oh, you fix [insert medical machine here]??' (no). In order: radiographers push buttons which make images (or treat patients, in radiotherapy); radiologists are doctors specialising in radiology (medical imaging), and engineers fix machines. (We just tell the engineer it's broken...)
Wikipedia1 helpfully describes medical physics as follows:
Medical physics is generally speaking the application of physics concepts, theories and methods to medicine.This must be very helpful for people who don't understand the adjectival suffix, but not otherwise. What physics concepts?
Well, as I said above, mainly radiation; to be specific, ionising radiation. That is, x-rays, radioactive materials, etc. Since that's the bulk of it, and that's what I'm working in, I'll come to the details of that later.
But as well as ionising radiation, we also work with non-ionising radiation: lasers (used to break up kidney stones, remove tattoos, etc.), ultrasound (obviously used in imaging, but also in interventional medicine), UV dermatological treatments (for psoriasis and certain skin cancers), and magnetic resonance imaging (MRI).
The main roles in a lot of this are quality assurance, and safety. We test machines; we look for patterns in response, for abnormalities, and we try to explain them. (Then we call the engineers...) We advise doctors, and other medical staff, on the safety issues with various types of non-ionising radiation (don't shine lasers into your eyes; don't take metallic power tools into an MRI room2; in terms of ultrasound, well, there's very little safety to advise on, which is one of the reasons I personally find it dull).
We also try to optimise imaging: obtaining the best quality image possible (for a definition of quality which depends on the clinical purpose), and writing computer programs to help with image processing and analysis. This is also to do with safety, in terms of reducing the dose of radiation needed to achieve an appropriate image quality.
In ionising radiation, there are three main areas: nuclear medicine, radiotherapy, diagnostic radiology; and covering all of these, radiation protection. I'll explain these in more detail in following posts.
1. en.wikipedia.org/wiki/Medical_physics [quotation retrieved 14/03/2013]. ↩
2. This really happened; it destroyed a very expensive machine which had only just been installed. ↩
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